****POSIX**** 条件锁需要互斥锁和条件两项来实现，虽然看起来没什么关系，但在运行时中，互斥锁将会与条件结合起来。线程将被一个互斥和条件结合的信号来唤醒。
首先初始化条件和互斥锁，当 ****ready_to_go**** 为 ****flase**** 的时候，进入循环，然后线程将会被挂起，直到另一个线程将 ****ready_to_go**** 设置为 ****true**** 的时候，并且发送信号的时候，该线程会才被唤醒。
pthread_mutex_t mutex;
pthread_cond_t condition;
Boolean ready_to_go = true;
void MyCondInitFunction()
{
pthread_mutex_init(&mutex);
pthread_cond_init(&condition, NULL);
}
void MyWaitOnConditionFunction()
{
// Lock the mutex.
pthread_mutex_lock(&mutex);
// If the predicate is already set, then the while loop is bypassed;
// otherwise, the thread sleeps until the predicate is set.
while(ready_to_go == false)
{
pthread_cond_wait(&condition, &mutex);
}
// Do work. (The mutex should stay locked.)
// Reset the predicate and release the mutex.
ready_to_go = false;
pthread_mutex_unlock(&mutex);
}
void SignalThreadUsingCondition()
{
// At this point, there should be work for the other thread to do.
pthread_mutex_lock(&mutex);
ready_to_go = true;
// Signal the other thread to begin work.
pthread_cond_signal(&condition);
pthread_mutex_unlock(&mutex);
}
